Critical infrastructures such as electricity, oil, gas, telecommunications, transportation, and water are essential to the functioning of modern economies and societies. As the world is increasingly interconnected, long-haul trans-regional, trans-national, or trans-continental links are playing a crucial role in transporting critical resources and information from one location to another. For example, it is known that submarine telecommunications cables carry over 95% of the global voice and data traffic. Russian gas that is delivered through the trans-European pipeline accounts for over a quarter of the total European consumption. Such critical infrastructure links are vulnerable to disasters and, if broken, can have severe social and economic consequences.
Among various natural disasters, earthquakes often cause the most catastrophic effects. For example, in 1987, the Ecuador earthquake resulted in the damage of nearly 70 km of the Trans-Ecuadorian oil pipeline. Loss of the pipeline deprived Ecuador of 60% of its export revenue, and it took 5 months to reconstruct the pipeline. In 2006, the Hengchun/Taiwan earthquake damaged eight submarine cables with a total of 18 cuts. As a result, Internet services in Asia were severely disrupted for several weeks, affecting many Asian countries. These events signify the impacts of earthquake hazards and the importance of enhancing the seismic resilience of critical infrastructure links.
There is a need to more reliably determine an optimal path of critical infrastructure link between two locations on the surface of the Earth, especially one that crosses a prone-to-damage area.